Error setting remote_listener

How to set remote_listener if the entry is incorrect. I am getting following error.

SQL> show parameter remote_listener

NAME                 TYPE    VALUE

------------------------------------ ----------- ------------------------------

remote_listener           string   bos-qa-rac-scan.americanwell.c

                         om:1521

I need to change the word rac to rac3. Below command does not work.

SQL> alter system set remote_listener = 'bos-qa-rac3-scan:1521' scope=both sid='*';

alter system set remote_listener = 'bos-qa-rac3-scan:1521' scope=both sid='*'

*

ERROR at line 1:

ORA-02097: parameter cannot be modified because specified value is invalid

ORA-00119: invalid specification for system parameter REMOTE_LISTENER

ORA-00141: all addresses specified for parameter LOCAL_LISTENER are invalid